Although navigation apparatuses of the foregoing type were initially limited to types integrally fixed to the vehicle, there have recently also been proposed easily-carried portable types, as well as detachable navigation apparatuses that further improve ease-of-use by enabling only the section with navigation functions to be mounted and dismounted (see, for example, Patent Reference 1 and Non-patent Reference 1).
According to the technology taught by Patent Reference 1, a navigation apparatus comprising a GPS receiver connected to a GPS antenna, a gyrosensor, a vehicle signal processor circuit including a vehicle speed signal, a display for displaying a map, and an ECU for overall control is equipped with a vehicle side unit provided on the vehicle side and a detachable unit detachably provided on the vehicle, and at least the gyrosensor and the vehicle signal processor circuit are mounted on the vehicle side, while the display and ECU are installed in the detachable unit to enable removal from the vehicle for use in the outside of the vehicle.
According to the technology taught by Non-Patent Reference 1, a unit (detachable side unit) configured to be attachable/detachable to/from an audio-combined main unit (vehicle side unit) is provided and the subject vehicle location can be corrected using a GPS signal and a wheel speed sensor output. Further, the detachably configured subunit has navigation capability even when removed from the main unit, thereby enabling use in the outside of the vehicle mounted with the main unit and destination searches and the like in the home.
Patent Reference 1: Japanese Patent No. 3376813
Non-Patent Reference: “Fujitsu Ten: ECLIPSE ‘AVN2227P’ to be Launched”, [on line], Apr. 19, 2007, Fujitsu-Ten Limited, located by search on Apr. 26, 2007, Internet URL,
http ://www.fujitsu-ten.co.jp/release/2007/04/20070419.html